Population Structure of Snow Gum (Eucalyptus pauciflora Sieb ex Spreng) Subalpine Woodland in Kosciusko National-Park

Abstract

Snow gum was sampled in 15 sites at altitudes from 1540 to 1820m. The population age structure reflects the incidence of fire and grazing, which have affected the woodland since 1900. Evidence for recruitment on three occasions prior to 1900 is given, and it is suggested that two of these may have arisen as a result of fire. Whereas pre-disturbance stem densities calculated from remnants of previous populations suggest densities of between 24 and 240 stems per hectare according to site, current stem densities arising from flushes of regeneration this century are calculated as between 700 and 5550 stems per hectare. In 1973, levels of failing stems within juvenile, mature and old subpopulations, while variable, suggest that it may be 100-200 or more years before stem densities approach the calculated pre-disturbance densities. The work raises park management issues: what structural forms of woodland are appropriate in the Park; what effect allowing natural senescence to thin existing woodland will have on fire hazard and other components of the ecosystem; the need for a long-term monitoring system.